如果Angular 6中的textarea为空，如何禁用复选框

Question

I have textarea and checkbox in my Angular template. Textarea can be with or without value, it depends of my api. I want to add attribute disabled to my checkbox if textarea empty, and does not add if textarea has it

Something like:

<textarea name="descriptionText" formControlName="descriptionText">
</textarea>
<input type="checkbox" [disabled]="!descriptionText.length" />

Answer 1

You can use ngModel to achieve this goal

<textarea [(ngModel)]="text"></textarea>
<input type="checkbox" [disabled]="!text || text.length <= 0" />

Adding !text check you can avoid to declare text var into your ts component.

Remember to import ngModel into your ts component like this:

import { NgModule } from '@angular/core';